The other thing with Rivero is that we might be able to basically use him as an Andrew Miller type guy, with Hudson being the closer for about a year and a half, and then re-assess after that. Nicasio is a UFA after this year, but maybe we can give him a small raise and keep him for a couple more. Clay Holmes will still be very young in 2019, but maybe if he doesn't work out as a starter, Taylor Hearn on the horizon, etc.
Rivero could of course transition into the role, but his age and the likely ability to be useful for multiple innings will make him most valuable as the most high leverage guy we have in late innings, especially if Hudson is able to equally handle high leverage ninth inning scenarios (but I think the way you draw it up ideally is that in a super closer game, Rivero might even be able to enter into the seventh inning and get through the eighth, or even do the sixth, seventh, and like a key batter starting the eighth, etc., in order to quell any comebacks).
Not great news to see some doubt about Taillon's changeup, but he's still getting results in limited innings, and generally not giving up any hard contact from what I see.